How do Zorin (don't like this one and the new 6.2 has problems with its desktop on my PC) and Cylon http://cylonlinux.weebly.com/ ( very nice eye candy) have compiz active without any proprietary drivers installed?

The Mesa 3D graphics libraries support OpenGL 2.x+ since 2007 Cf: http://www.mesa3d.org/ So any current distro supports OpenGL 2.x+ unless your GPU hardware is too old to support even software OpenGL 2.x rendering.